[llvm] [clang] [PGO][GlobalValue][LTO]In GlobalValues::getGlobalIdentifier, use semicolon as delimiter for local-linkage varibles. (PR #74008)

[Mingming Liu via cfe-commits]

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@@ -300,12 +316,8 @@ getIRPGONameForGlobalObject(const GlobalObject &GO,
                             GlobalValue::LinkageTypes Linkage,
                             StringRef FileName) {
   SmallString<64> Name;
-  if (llvm::GlobalValue::isLocalLinkage(Linkage)) {
-    Name.append(FileName.empty() ? "<unknown>" : FileName);
-    Name.append(";");
-  }
   Mangler().getNameWithPrefix(Name, &GO, /*CannotUsePrivateLabel=*/true);
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minglotus-6 wrote:

> I guess the name is still mangled, but I used Mangler().getNameWithPrefix() to get the linkage name.

When raw profiles stores (optionally filename prefixed) linkage names while global identifier uses the (filename prefixed) mangled name, the particular use case would be broken. Is it possible to convert objective-c mangled name to linkage name (needed by linker) in the post-processing of raw profiles? And do you think it make sense for the use case of D156569?

Say raw profiles still stores `[filepath;]mangled-name`, and `llvm-profdata` takes it to generate the linkage name that `-symbol-ordering-file` wants.

https://github.com/llvm/llvm-project/pull/74008